992B Question

[James Wrobel]

I have a 992B in which the stem is losing its tension near full wind. It acts like the outer mainspring hook is jumping out of place. The watch will still run down and re-wind.

What kind of end is on this mainspring, and can it come loose?

Thanks,
jjw

 

[Skutt50]

Could very well be that the hook/Tend etc is comming loose from the barrel wall. I believe there is more than one type of mainspring end on these movements. You need to remove the mainspring and inspect it to identify/verify the problem.

 

[John Runciman]

I'm attaching the technical guide for the Hamilton 992B. Also have an image of the mainspring as far as I know there's only one End for the spring. But they're different thicknesses for the steel spring and for the DYNAVAR.

Then the only way you going to tell with the mainspring is doing is to open the barrel and see.

 

[James Wrobel]

Thanks for this bulletin. I learned that the screw on the winding wheel is right-handed. I would have been messing around with that for days.

jjw

 

[James Wrobel]

Update: upon further inspection, I found that the mainspring is not slipping. It's something in the winding wheel. I will investigate, and if I find anything interesting, I will start another post.

Thanks all,
jjw

 

[James Wrobel]

Update:
Thanks to John, when I learned that the screw on the winding wheel was right-handed, I suspected that it might just be loose. Sure enough, it was, and now the watch is winding again.

There is a good reason why that screw is normally left-handed.

Thanks, all.
Relief,
jjw